Jingjing Zhou

Discovery and Validation of Plasma Biomarkers for Major Depressive Disorder Classification Based on Liquid Chromatography–Mass Spectrometry

Major depressive disorder (MDD) is a debilitating mental disease with a pronounced impact on the quality of life of many people; however, it is still difficult to diagnose MDD accurately. In this study, a nontargeted metabolomics approach based on ultra-high-performance liquid chromatography equipped with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was used to find the differential metabolites in plasma samples from patients with MDD and healthy controls. Furthermore, a validation analysis focusing on the differential metabolites was performed in another batch of samples using a targeted approach based on the dynamic multiple reactions monitoring method. Levels of acyl carnitines, ether lipids, and tryptophan pronouncedly decreased, whereas LPCs, LPEs, and PEs markedly increased in MDD subjects as compared with the healthy controls. Disturbed pathways, mainly located in acyl carnitine metabolism, lipid metabolism, and tryptophan metabolism, were clearly brought to light in MDD subjects. The binary logistic regression result showed that carnitine C10:1, PE-O 36:5, LPE 18:1 sn-2, and tryptophan can be used as a combinational biomarker to distinguish not only moderate but also severe MDD from healthy control with good sensitivity and specificity. Our findings, on one hand, provide critical insight into the pathological mechanism of MDD and, on the other hand, supply a combinational biomarker to aid the diagnosis of MDD in clinical usage.

Hippocampal synaptic dysregulation of exo/endocytosis-associated proteins induced in a chronic mild-stressed rat model.

Although major depressive disorder (MDD) is a serious neuropsychiatric illness, its pathogenesis remains unclear. Current evidence suggests that the abnormal transmission and plasticity of hippocampal synapses play an important role in the pathogenesis of MDD. In this study, a two-dimensional gel-based proteomic approach to profile alterations of synaptosome protein expression was applied in the hippocampus of rats subjected to chronic mild stress. Through mass spectrometry and database searching, 19 differentially expressed proteins were identified, of which 5 were up-regulated and 14 were down-regulated in the chronic mild-stressed group as compared with the control group. Subsequently, several proteins of interest were further validated by Western blotting. A detailed analysis of protein functions and disease relevance revealed that synaptic exo/endocytosis-associated proteins were dysregulated in the chronic mild-stressed rats. The present study is the first reported synaptoproteomic analysis of the chronic mild-stressed rat hippocampus. The synaptic exo/endocytosis-associated proteins may participate in a central mechanism that underlies the abnormal transmission and plasticity of hippocampal synapses found in the chronic mild-stressed rats, and provides guidance to advance our understanding of the pathogenesis of MDD.

Divergent Urinary Metabolic Phenotypes between Major Depressive Disorder and Bipolar Disorder Identified by a Combined GC-MS and NMR Spectroscopic Metabonomic Approach.

Bipolar disorder (BD) is a complex debilitating mental disorder that is often misdiagnosed as major depressive disorder (MDD). Therefore, a large percentage of BD subjects are incorrectly treated with antidepressants in clinical practice. To address this challenge, objective laboratory-based tests are needed to discriminate BD from MDD patients. Here, a combined gas chromatography-mass spectrometry (GC-MS)-based and nuclear magnetic resonance (NMR) spectroscopic-based metabonomic approach was performed to profile urine samples from 76 MDD and 43 BD subjects (training set) to identify the differential metabolites. Samples from 126 healthy controls were included as metabolic controls. A candidate biomarker panel was identified by further analyzing these differential metabolites. A testing set of, 50 MDD and 28 BD subjects was then used to independently validate the diagnostic efficacy of the identified panel using an area under the receiver operating characteristic curve (AUC). A total of 20 differential metabolites responsible for the discrimination between MDD and BD subjects were identified. A panel consisting of six candidate urinary metabolite biomarkers (propionate, formate, (R*,S*)2,3-dihydroxybutanoic acid, 2,4-dihydroxypyrimidine, phenylalanine, and β-alanine) was identified. This panel could distinguish BD from MDD subjects with an AUC of 0.913 and 0.896 in the training and testing sets, respectively. These results reveal divergent urinary metabolic phenotypes between MDD and BD. The identified urinary biomarkers can aid in the future development of an objective laboratory-based diagnostic test for distinguishing BD from MDD patients.

Sex-Specific Urinary Biomarkers for Diagnosing Bipolar Disorder

Sex-based differences are prominent in affective disorders, but there are no biomarkers available to support sex-specific, laboratory-based diagnostics for male and female bipolar disorder (BD) patients. Here, a NMR-based metabonomic approach was used to preliminarily identify sex-specific urinary metabolite biomarkers for diagnosing male and female BD patients. A male-specific biomarker panel consisting of four metabolites (α-hydroxybutyrate, choline, formate, and N-methylnicotinamide) effectively discriminated between male BD and healthy controls (HC) subjects, achieving an area under the receiver operating characteristic curve (AUC) of 0.942. A female-specific biomarkers panel consisting of four metabolites (α-hydroxybutyrate, oxalacetate, acetone, and N-methylnicotinamide) effectively discriminated between female BD and HC subjects, achieving an AUC of 0.909. The male-specific biomarker panel displayed low discriminatory power in the female group, and the female-specific biomarker panel displayed low discriminatory power in the male group. Moreover, several other metabolites showed different trends between male and female BD subjects. These findings suggest that male and female BD patients have distinct biomarker fingerprints and that these two sex-specific biomarker panels may serve as effective diagnostic tools in distinguishing male and female BD patients from their healthy counterparts. Our work may provide a window into the mechanisms underlying the pathoetiology of BD in both men and women.

Do soy isoflavones improve cognitive function in postmenopausal women? A meta-analysis.

ObjectiveSeveral studies have demonstrated that soy isoflavone (SIF) supplementation can improve aspects of cognitive function. However, these findings remain controversial. We aimed to quantify the effects of SIF supplementation on improving cognitive function in postmenopausal women. MethodsDatabases and relevant Websites were searched for relevant studies up to March 2014. Two reviewers independently verified all potentially suitable randomized controlled trials (RCTs) using inclusion and exclusion criteria, and the quality of identified RCTs was assessed using the Jadad scale and the Risk of Bias Tool from the “Cochrane handbook for systematic reviews of interventions.” Any disagreement on study quality or data extraction was resolved by consensus; a third reviewer was consulted if needed. Standardized mean differences (SMDs) in cognitive function test scores were calculated between SIF-treated and placebo-treated groups. ResultsWe conducted a meta-analysis of 10 placebo-controlled RCTs of SIF supplementation (1,024 participants; treatment duration of 6 wk to 30 mo). The overall SMD in summary cognitive function test scores (0.08) was statistically significant (95% CI, 0.02-0.15; P = 0.014). The summary SMD for visual memory (0.10) was statistically significant (95% CI, 0.02-0.18; P = 0.016). In subgroup analyses, the statistically significant SMDs were as follows: 0.12 (95% CI, 0-0.25; P = 0.044) for non-US countries; 0.16 (95% CI, 0.05-0.28; P = 0.004) for mean age younger than 60 years; and 0.15 (95% CI, 0.03-0.27; P = 0.011) for treatment duration less than 12 months. ConclusionsSIF supplementation seems to have a positive effect on improving summary cognitive function and visual memory in postmenopausal women. There may be a critical window of opportunity in initiating SIF use at an earlier age in postmenopausal women, and geography and treatment duration seem to be factors influencing the effects of SIF supplementation. All individuals in the included studies should be followed up to observe the incidence rates of Alzheimer’s disease and dementia, and future studies should report any adverse effects of SIF supplementation.

Metabolite signature for diagnosing major depressive disorder in peripheral blood mononuclear cells

BACKGROUND Major depressive disorder (MDD) is a serious debilitating psychiatric disorder. However, the molecular mechanisms of MDD remain largely unknown, and no objective laboratory-based tests are available to diagnose this disorder. METHODS A gas chromatography-mass spectrometry (GC-MS) based metabolomic approach was used to compare peripheral blood mononuclear cells (PBMC) metabolic profiling of 50 first onset drug-naïve MDD subjects and 50 healthy controls (training samples), to identify potential metabolite biomarkers for MDD. An independent sample cohort including 58 MDD patients, 40 schizophrenia (SCZ) patients and 56 healthy controls (test samples) was used to validate diagnostic generalizability and specificity of identified biomarkers. RESULTS 17 PBMC metabolites responsible for discriminating MDD group from healthy control group were identified. These metabolites were mainly involved in disturbances of energy and neurotransmitter metabolism. This PBMC metabolite signature could effectively discriminate MDD subjects from the healthy controls with an AUC of 0.926 in training samples and 0.870 in test samples. Moreover, this metabolite signature enabled distinguishing MDD subjects from schizophrenia subjects with an AUC of 0.899. LIMITATIONS This study was limited by potential confounding effects of different drug treatments in some MDD and schizophrenia subjects, and lack of animal studies to further validate the identified metabolite pathways in MDD. CONCLUSION These findings suggest that early disturbances of PBMC energy and neurotransmitter metabolism may be associated with the onset of MDD. This PBMC metabolite signature may facilitate development of a laboratory-based diagnostic test for MDD.

1H NMR-Based Metabolic Profiling Reveals the Effects of Fluoxetine on Lipid and Amino Acid Metabolism in Astrocytes

Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), is a prescribed and effective antidepressant and generally used for the treatment of depression. Previous studies have revealed that the antidepressant mechanism of fluoxetine was related to astrocytes. However, the therapeutic mechanism underlying its mode of action in astrocytes remains largely unclear. In this study, primary astrocytes were exposed to 10 µM fluoxetine; 24 h post-treatment, a high-resolution proton nuclear magnetic resonance (1H NMR)-based metabolomic approach coupled with multivariate statistical analysis was used to characterize the metabolic variations of intracellular metabolites. The orthogonal partial least-squares discriminant analysis (OPLS-DA) score plots of the spectra demonstrated that the fluoxetine-treated astrocytes were significantly distinguished from the untreated controls. In total, 17 differential metabolites were identified to discriminate the two groups. These key metabolites were mainly involved in lipids, lipid metabolism-related molecules and amino acids. This is the first study to indicate that fluoxetine may exert antidepressant action by regulating the astrocyte’s lipid and amino acid metabolism. These findings should aid our understanding of the biological mechanisms underlying fluoxetine therapy.

Human borna disease virus infection impacts host proteome and histone lysine acetylation in human oligodendroglia cells

Abstract Background Borna disease virus (BDV) replicates in the nucleus and establishes persistent infections in mammalian hosts. A human BDV strain was used to address the first time, how BDV infection impacts the proteome and histone lysine acetylation (Kac) of human oligodendroglial (OL) cells, thus allowing a better understanding of infection-driven pathophysiology in vitro. Methods Proteome and histone lysine acetylation were profiled through stable isotope labeling for cell culture (SILAC)-based quantitative proteomics. The quantifiable proteome was annotated using bioinformatics. Histone acetylation changes were validated by biochemistry assays. Results Post BDV infection, 4383 quantifiable differential proteins were identified and functionally annotated to metabolism pathways, immune response, DNA replication, DNA repair, and transcriptional regulation. Sixteen of the thirty identified Kac sites in core histones presented altered acetylation levels post infection. Conclusions BDV infection using a human strain impacted the whole proteome and histone lysine acetylation in OL cells.

Disorganized cortical thickness covariance network in major depressive disorder implicated by aberrant hubs in large-scale networks

Major depressive disorder is associated with abnormal anatomical and functional connectivity, yet alterations in whole cortical thickness topology remain unknown. Here, we examined cortical thickness in medication-free adult depression patients (n = 76) and matched healthy controls (n = 116). Inter-regional correlation was performed to construct brain networks. By applying graph theory analysis, global (i.e., small-worldness) and regional (centrality) topology was compared between major depressive disorder patients and healthy controls. We found that in depression patients, topological organization of the cortical thickness network shifted towards randomness, and lower small-worldness was driven by a decreased clustering coefficient. Consistently, altered nodal centrality was identified in the isthmus of the cingulate cortex, insula, supra-marginal gyrus, middle temporal gyrus and inferior parietal gyrus, all of which are components within the default mode, salience and central executive networks. Disrupted nodes anchored in the default mode and executive networks were associated with depression severity. The brain systems involved sustain core symptoms in depression and implicate a structural basis for depression. Our results highlight the possibility that developmental and genetic factors are crucial to understand the neuropathology of depression.

Knock-Down of Endogenous Bornavirus-Like Nucleoprotein 1 Inhibits Cell Growth and Induces Apoptosis in Human Oligodendroglia Cells

Endogenous bornavirus-like nucleoprotein elements (EBLNs) have been discovered in the genomes of various animals including humans, whose functions have been seldom studied. To explore the biological functions of human EBLNs, we constructed a lentiviral vector expressing a short-hairpin RNA against human EBLN1, which successfully inhibited EBLN1 expression by above 80% in infected human oligodendroglia cells (OL cells). We found that EBLN1 silencing suppressed cell proliferation, induced G2/M phase arrest, and promoted apoptosis in OL cells. Gene expression profiling demonstrated that 1067 genes were up-regulated, and 2004 were down-regulated after EBLN1 silencing. The top 10 most upregulated genes were PI3, RND3, BLZF1, SOD2, EPGN, SBSN, INSIG1, OSMR, CREB3L2, and MSMO1, and the top 10 most-downregulated genes were KRTAP2-4, FLRT2, DIDO1, FAT4, ESCO2, ZNF804A, SUV420H1, ZC3H4, YAE1D1, and NCOA5. Pathway analysis revealed that these differentially expressed genes were mainly involved in pathways related to the cell cycle, the mitogen-activated protein kinase pathway, p53 signaling, and apoptosis. The gene expression profiles were validated by using quantitative reverse transcription polymerase chain reaction (RT-PCR) for detecting these 20 most-changed genes. Three genes closely related to glioma, RND3, OSMR, and CREB3L2, were significantly upregulated and might be the key factors in EBLN1 regulating the proliferation and apoptosis of OL cells. This study provides evidence that EBLN1 plays a key role in regulating cell life and death, thereby opening several avenues of investigation regarding EBLN1 in the future.